What does the heliocentric model of the solar system state?

a- all of the planets and the sun orbit earth

b- only the moon and earth orbit the sun

c- earth and the other planets orbit the sun

Ameter stick is pivoted at the 0.50-m line. a 3.0-kg object is hung from the 0.15-m line. where should a 5.0-kg object be hung to achieve equilibrium (the meter stick oriented horizontal and motionless)?